$46.08 – 2.1-inch Water-cooled IPS USB Secondary Screen (Banggood, Aliexpress: 2.1-inch Water-cooled IPS USB Secondary Screen Built-in Screen Monitor Computer Status 360-degree Rotation 480×480 LCD Display CPU GPU RAM HDD Monitoring Device – White (the best price with coupon)).
You can get 2.1-inch Water-cooled IPS USB Secondary Screen for $46.08 with coupon (from Banggood). Basically copy coupon, view price history or create e-mail price alert. Best price?
Latest coupon and price update (UTC):
Banggood ($46.08)
Banggood warehouse is located in China. I’m afraid that there’s no working coupon in Banggood. Is it expensive? From what I can see this price is higher than average price ($30.99).
Link: Banggood product page
Price: $46.08
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/feV
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Do you need price history chart (for all/most countries) for 2.1-inch Water-cooled IPS USB Secondary Screen? There we go. The lowest price was: $29.99.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).